St. Paul's UMC, Houston. 
Schantz Organ.

Pipe Ranks and Divisions
Introduction

An organ pipe sounds only a single pitch. For full length keyboard, it is then necessary to have a separate pipe for each pitch, in order that each key can sound the appropriate pitch when it is played. In addition, the individual pipes must be made and voiced so that the same timbre is obtained from each pipe for a given stop. A complete set of 32 pipes (for pedal stops) or 61 pipes (for manual stops) so constructed is called a rank. In the case of compound stops, a separate rank of pipes is necessary for each note that the stop sounds on a single key. Thus a Mixture IV will have four full ranks of pipes, a Cornet V five ranks, and so forth.

Ranks and Pipe Placement

A rank of pipes can be identified visually. With some exceptions, the pipes of a given rank will be made of the same material and be built alike. That is to say, the rank will consist of all stopped flue pipes made of wood, or of all open metal flue pipes, or of all reed pipes with conical metal resonators. Exceptions to this general principle come in cases where a particular pipe design might not be appropriate for a specific range within the rank itself. An 8' Rohrflöte, for example, a rank of partially closed flue pipes, might be made with fully closed pipes in its first octave, because the timbre of those pipes will be a better continuation of the desired tonal quality into the lower register. Similarly, in the upper register of a 4' Clairon, a rank of reed pipes with conical resonators, there might be a shift to open flue pipes in the top-most octave, because they are more stable and easier to regulate tonally than extremely small reed pipes. In such cases, it is necessary to voice the different pipes so that they sound as much as possible like the rest of the rank.

Although a rank will contain all the pipes necessary to play the full range of the keyboard associated with it, the individual pipes of a rank are not always placed in keyboard order, nor are they always placed in a straight line.

Twelve
Pipe Diameters, ChromaticWhen pipes are small - - as in the case of a 2' or higher stop, the pipes might appear in a straight line if a chromatic order of pipes is followed. In the case of larger pipes, the pipes might be placed in a staggered line in order to prevent the entire rank from taking up too much space. In the diagram, each circle represents the diameter of a pipe in the first octave of an 8' Principal. As the pitches indicate, chromatic order is followed in the rank moving from front to back through a staggered line.

The Photograph below shows a small manual division in which the pipes are arranged in a similar order. The rank at the front is a wooden 4' Gedeckt, with the pipes placed in a staggered line from left to right. Behind the Gedeckt are the other ranks of this division: a 2' Gemshorn (barely visible), a 2 2/3' Quint, and a 4' Principal. All ranks follow the same pattern of a staggered line, so that the pipes sounded by the lowest key are all in line from front to back, and so on across the width of the chest.

BSC, Schantz Organ

Twelve
Pipe
Diameters, DividedWhen chromatic order is not followed in the placement of a rank of pipes, several possibilities may be found. One of the most common plans is to place the first pipe in the center, and to arrange the rest of the rank in alternation to the left and right of the center pipe, as shown in this diagram. When a rank of pipes is arranged in this way, a pyramid shape results, with all the pipes on one side forming a whole- tone scale on C, and those on the other a whole-tone scale on C#. It is common to refer to the two sides of ranks so arranged as the "C side" and the "C# side."

The photograph below shows a rank of stopped metal pipes in the rear of the chest, with several higher-pitched ranks arranged in front of the first one. 22 The center pipe of each rank is the one that sounds when the lowest C of the keyboard is played. In ascending chromatic order, the rest of the pipes follow the same pattern outward from the center, moving from right to left in alternation, shown in the diagram above.

FUMC Birmingham. Positiv
Pipes.

Pipe Divisions and Placement

In a typical organ with more than one keyboard, the stops and the ranks controlled by them are separated into different divisions. The most common and straightforward disposition of ranks of pipes is to group all of them that are played from a single keyboard on a separate chest. Ranks of pipes grouped in this way are made and voiced to be used together in various combinations, and they present a coherent sound when used in this way. A separate chest (more than one in the case of large instruments) with its pipes and played from a single manual or pedal keyboard is called a division. In some situations, a division may be referred to as an organ, a component of the larger instrument. Thus a reference to the Swell organ is equivalent to using the term Swell division. In common use, either term may be shortened to simply the Swell.

On a given instrument, separate divisions have tonal properties that contrast with one another in timbre, dynamics, pitch range or physical location of the pipes. In different countries and in different periods of the history of the organ, the ways in which these contrasts are made can be very specific, but within each type of organ there is some consistency. In an organ built in the US, the most common divisions and their characteristics are:

Although the common practice is to place all pipes of a division on a single chest, this is not always possible, particularly in the case of larger organs. Occasionally, a division will be split on two chests even though it may be small. Considerations of space combined with visual aesthetics may result in the splitting of a division onto separate chests that constitute a "C side" and C# side" that can be placed in different locations. For example, in the photograph below, the red rectangles identify the two sections of a split Great division, with the C side on the left and the C# side on the right. The blue rectangles outline the similarly divided pedal. 21

First Baptist Church,
Decatur, Georgia. 
Holtkamp Facade.


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© 1998, James H. Cook